Argon beam coagulators have been known for many years, and examples are given in U.S. Pat. Nos. 4,040,426, 6,039,736 and 6,197,026. The first example is an end-effect instrument, in which the ionised gas exits through the end of the instrument, while the latter two examples are directed at side-effect instruments, in which the ionised gas exits the instrument though an aperture in the side of the instrument. Such instruments are often referred to as APC instruments (Argon Plasma Coagulation).
The majority of these instruments perform purely tissue coagulation and have no tissue cutting capability. Where such instruments do have a tissue cutting capability, this is achieved by a tissue contacting needle or other electrode. Examples are U.S. Pat. Nos. 5,088,997 and 6,702,812, which both provide a forwardly extending tissue-contacting electrode to perform the cutting of tissue.